Peri-strut low intensity areas and in-scaffold neointima growth after bioresorbable scaffold implantation in STEMI. A serial optical coherence tomography study.

BACKGROUND: Peri-strut low intensity areas (PLIA) visualized by optical coherence tomography (OCT) have been related to neointimal proliferation and increased incidence of target lesion revascularization in stable coronary artery disease. The aim of this study was to determine the association between PLIA by OCT and the long-term vascular healing response after bioresorbable scaffold (BRS) implantation in the setting of ST-segment elevation myocardial infarction (STEMI). METHODS: This is a single-centre, longitudinal, cohort study with a serial: baseline, 1, 2 and 5 years OCT evaluation of neointimal response (lumen area and neoatherosclerosis) after percutaneous coronary intervention (PCI) with BRS Absorb™ 1.0 implantation in patients presenting with STEMI. PLIA was analyzed in every cross section and scored: 0-no PLIA; 1-PLIA < 1 quadrant; 2-PLIA ≥ 1 and <2 quadrants; 3-PLIA ≥ 2 and <3 quadrants; 4-PLIA in ≥3 quadrants. RESULTS: Of the 23 patients implanted BRS, 18 completed 2-year follow-up, whereas complete OCT data up to 5 years were available in 12 patients. Presence of PLIA was identified in 100% patients at 1 and 2 years, whereas at 5 years neither PLIA nor scaffold struts were visualized by OCT. Neoatherosclerosis was identified in 73,68% patients after 1 year and in all patients at 2 and 5 years. The mean PLIA score > 1 at 2 years was associated with greater percentage of minimum lumen area decrease after 2 years from index procedure. CONCLUSIONS: The extent of PLIA by OCT at 2 years after primary PCI with BRS was associated with lumen area decrease. Neoatherosclerosis formation was detected in all patients at 2 and 5 years. PLIA assessment could serve as an additive means to predict neointimal healing pattern after next generation BRS implantation.